Perhaps the best-known example of wireless personal area network (PAN) technology is Bluetooth Standard, which operates in the 2.4 GHz ISM band. Bluetooth is a short-range radio network, originally intended as a cable replacement. Bluetooth Technical Specifications are published by the Bluetooth SIG, Inc. Bluetooth Specification version 2.0+EDR, published Oct. 15, 2004 has the original functional characteristics of the first version Bluetooth Basic Rate (BR) and adds the Enhanced Data Rate (EDR) feature. Bluetooth Specification version 2.1+EDR, published Jul. 26, 2007 for Basic Rate/Enhanced Data Rate (BR/EDR), added definitions for new features: Encryption Pause Resume, Erroneous Data reporting, Extended Inquiry Response, Link Supervision Timeout Event, Packet Boundary Flag, Secure Simple Pairing, Sniff Subrating. Bluetooth Specification version 3.0+HS, published Apr. 21, 2009, updated the standard to integrate the Alternate MAC/PHY and Unicast Connectionless Data features.
On Apr. 20, 2009, Bluetooth SIG presented the new Bluetooth Low Energy protocol. Bluetooth Low Energy (LE) is a communication protocol directed to optimize power consumption of devices while being connected to other devices. The Bluetooth Low Energy packets include a preamble used for radio synchronization, an access address used for physical link identification, a shorter protocol data unit (PDU) to carry the payload data and the PDU header information, and a cyclic redundancy code (CRC) to ensure correctness of the data in the PDU.
On Jun. 30, 2010, the Bluetooth SIG published the Bluetooth Core Specification, Version 4.0 (incorporated herein by reference), which includes the Bluetooth Low Energy (LE) protocol for products that require lower power consumption, lower complexity, and lower cost than would be possible using the BR/EDR protocol. Bluetooth LE is designed for applications requiring lower data rates and shorter duty cycles, with a very-low power idle mode, a simple device discovery, and short data packets. Bluetooth LE devices employ a star topology, where one device serves as a master for a plurality of slave devices, the master dictating connection timing by establishing the start time of the first connection event and the slave devices transmitting packets only to the master upon receiving a packet from the master. According to Bluetooth LE communication protocol all connections are point-to-point connections between two devices (the master and the slave).